1. Field of the Invention
The present invention relates to a service providing apparatus and a data processing apparatus, which are connected to terminal devices via a network such that they can communicate with each other, and are capable of providing service using their functions for the terminal devices, an information providing method, a program for implementing the method, and a storage medium storing the program.
2. Description of the Related Art
In recent years, with the spread of large-scale networks such as the Internet, network technology has been dramatically improved. Under such circumstance, the technology called Web service which provides services on various networks through the linkage of devices connected on the networks using WWW-related technology has widely drawn attention. Among such services, a so-called printing service in which a printing device connected to terminal devices via a network provides service using its functions for the terminal devices has been increasingly used. In this printing service, a terminal device on a network selects a printing device with desired functions from among a plurality of printing devices which are capable of accepting a printing request from the terminal device and carrying out printing, so that printing is carried out using the selected printing device.
As an example of devices which provide such a printing service, a printing device which notifies the start of a service, and lays open device information and service contents on a network has been disclosed in Japanese Laid-Open Patent Publication (Kokai) No. H11-191086. A terminal device connected to the network can access the service on the network by acquiring or retrieving the laid-open information. If the terminal device on the network registers the acquired device information and service contents, it does not have to acquire or retrieve device information on the printing device and service contents each time it uses the service.
For example, the printing device capable of providing the printing service as above notifies the start of service and publicizes device information and service contents, and the terminal device acquires and registers service contents provided by the printing device, in the following ways.
The printing device which provides service, when activated, starts the printing service and transmits a start notification packet which notifies the start of service to a network. On this occasion, the printing device acquires its profile information and service contents which can be provided from the inside of the device, and creates a DDF (Device Description File) in which device information is described and an SDF (Service Description File) in which the contents of service are described. If the printing device which has transmitted the start notification packet to the terminal device is not registered in a terminal device which has received the start notification packet, the terminal device transmits a request to acquire the DDF and the SDF to the printing device according to information included in the start notification packet. Upon reception of the request, the printing device transmits the DDF and the SDF in response to the request, and the terminal device acquires and registers information such as device information on the printing device and service contents according to the DDF and the SDF received from the printing device.
In the case where a plurality of printing devices which provide printing services as above exist on the network, the terminal device registers services provided by the printing devices in the above described way.
In the case where printing is carried out through the operation of a terminal device which has registered services provided by printing devices on a network as described above, the terminal device selects a printing device providing a desired printing service according to information on the contents of the registered services to be provided by the printing devices, and transmits a printing request to the selected printing device to carry out printing.
For example, referring to FIGS. 17A and 17B, a description will now be given of how the printing device is started and the start of service is notified. FIG. 17A is a diagram showing timing in which the start of the conventional printing device and the start of the service are notified, and FIG. 17B is a diagram showing timing in which the start of the printing device and the start of the service are notified in the case where a finisher unit which sorts and/or staples printed matters and a double-sided printing unit are attached or removed after power supply to the printing device is turned off.
A start notification which is transmitted for notification of the start of the printing device and the start of service describes the effective period of the notification, and when the effective period expires, information registered in the terminal device is automatically deleted.
As shown in FIG. 17A, the printing device, upon activation, transmits a start notification packet. The printing device then transmits an update notification packet which, before the effective period of the service expires, updates expiration date (life time) corresponding to the service thereof so as to renew the effective period of the service and allow each terminal device to register information on its service according to each update notification. The each terminal device registers information on the service and expiration date corresponding to the service in accordance with the start notification packet and updates the registered expiration date in accordance with the update notification packet. This update notification packet is transmitted at regular intervals, and the contents thereof are the same as those of the start notification packet.
In ending the service, the printing device transmits an end notification packet which notifies the end of the service to each terminal device. Upon reception of the end notification packet, the terminal device confirms that the printing device has ended the service, and deletes the registered contents of the service.
There may be a case where, within the effective period of the start notification given by the printing device registered in the terminal device, the contents of the service are changed due to a change in the status of the printing device. In such a case, the printing device updates its DDF and SDF, and transmits only a start notification packet. However, since the effective period of the start notification of the printing device registered in the terminal device has not yet expired, the terminal device does not try to acquire the updated DDF and SDF in response to the start notification packet. Consequently, the terminal device cannot detect the change in the contents of the service.
Therefore, when the contents of the service are changed due to a change in the status of the printing device, the printing device transmits an end notification packet. As a result, the contents of the service registered in the terminal device are deleted. Thereafter, the printing device transmits a start notification packet again. As a result, the terminal device acquires the updated DDF and SDF in response to the start notification packet, and registers the contents of the service again.
However, there may be a case where power supply to the printing device is suddenly turned off, and the end notification packet cannot be transmitted. For example, the user turns off power supply to the printing device so as to attach or remove a finisher unit which sorts and/or staples printed matters, or a double-sided printing unit. Then, as shown in FIG. 17B, after power supply to the printing device is turned off, the finisher unit or the double-sided printing unit is attached or removed, which changes the contents of the service provided by the printing device. In this case, when power supply is turned on again, a start notification packet is transmitted, but at this time point, the effective period of the service based on the start or update notification packets has not yet expired. Therefore, the terminal device determines that the start notification packet is indicative of a notification for renewing the effective period, and does not acquire the DDF and SDF updated by the printing device. As a result, even though the contents of the service provided by the printing device have been changed, the terminal device cannot know and register the changed contents of the service.
As stated above, in the case where there is a change in the contents of a service within a period of time from turning-off to turning-on of power supply to the printing device, the terminal device may not acquire the changed contents of the service.